includes/IP.php

   1 <?php
   2 /**
   3  * Functions and constants to play with IP addresses and ranges
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Ashar Voultoiz <hashar at free dot fr>
  22  */
  23
  24 // Some regex definition to "play" with IP address and IP address blocks
  25
  26 // An IP is made of 4 bytes from x00 to xFF which is d0 to d255
  27 define( 'RE_IP_BYTE', '(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|0?[0-9]?[0-9])' );
  28 define( 'RE_IP_ADD' , RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE );
  29 // An IPv4 block is an IP address and a prefix (d1 to d32)
  30 define( 'RE_IP_PREFIX', '(3[0-2]|[12]?\d)' );
  31 define( 'RE_IP_BLOCK', RE_IP_ADD . '\/' . RE_IP_PREFIX );
  32 // For IPv6 canonicalization (NOT for strict validation; these are quite lax!)
  33 define( 'RE_IPV6_WORD', '([0-9A-Fa-f]{1,4})' );
  34 define( 'RE_IPV6_GAP', ':(?:0+:)*(?::(?:0+:)*)?' );
  35 define( 'RE_IPV6_V4_PREFIX', '0*' . RE_IPV6_GAP . '(?:ffff:)?' );
  36 // An IPv6 block is an IP address and a prefix (d1 to d128)
  37 define( 'RE_IPV6_PREFIX', '(12[0-8]|1[01][0-9]|[1-9]?\d)');
  38 // An IPv6 IP is made up of 8 octets. However abbreviations like "::" can be used.
  39 // This is lax! The number of colon groups is checked (1 to 7) but
  40 // the number of double colons is not validated (must be 0 to 1).
  41 define( 'RE_IPV6_ADD',
  42         '(' .
  43                 ':(:' . RE_IPV6_WORD . '){1,7}' . // starts with "::"
  44         '|' .
  45                 RE_IPV6_WORD . '(:{1,2}' . RE_IPV6_WORD . '){0,6}::' . // ends with "::"
  46         '|' .
  47                 RE_IPV6_WORD . '(:{1,2}' . RE_IPV6_WORD . '){1,7}' . // neither of the above
  48         ')'
  49 );
  50 define( 'RE_IPV6_BLOCK', RE_IPV6_ADD . '\/' . RE_IPV6_PREFIX );
  51 // This might be useful for regexps used elsewhere, matches any IPv6 or IPv6 address or network
  52 define( 'IP_ADDRESS_STRING',
  53         '(?:' .
  54                 RE_IP_ADD . '(\/' . RE_IP_PREFIX . '|)' . // IPv4
  55         '|' .
  56                 RE_IPV6_ADD . '(\/' . RE_IPV6_PREFIX . '|)' . // IPv6
  57         ')'
  58 );
  59
  60 /**
  61  * A collection of public static functions to play with IP address
  62  * and IP blocks.
  63  */
  64 class IP {
  65         /**
  66          * Given a string, determine if it as valid IP.
  67          * Note: Unlike isValid(), this looks for networks too.
  68          * @param $ip string possible IP address
  69          * @return string
  70          */
  71         public static function isIPAddress( $ip ) {
  72                 if ( !$ip ) {
  73                         return false;
  74                 }
  75                 if ( is_array( $ip ) ) {
  76                         throw new MWException( 'invalid value passed to ' . __METHOD__ );
  77                 }
  78                 return preg_match( '/^' . IP_ADDRESS_STRING . '$/', $ip )
  79                         && ( substr_count( $ip, '::' ) <= 1 ); // IPv6 IPs with 2+ "::" are ambiguous
  80         }
  81
  82         /**
  83          * Given a string, determine if it as valid IP in IPv6 only.
  84          * Note: Unlike isValid(), this looks for networks too.
  85          * @param $ip string possible IP address
  86          * @return string
  87          */
  88         public static function isIPv6( $ip ) {
  89                 if ( !$ip ) {
  90                         return false;
  91                 }
  92                 if ( is_array( $ip ) ) {
  93                         throw new MWException( 'invalid value passed to ' . __METHOD__ );
  94                 }
  95                 return preg_match( '/^' . RE_IPV6_ADD . '(\/' . RE_IPV6_PREFIX . '|)$/', $ip )
  96                         && ( substr_count( $ip, '::' ) <= 1 ); // IPv6 IPs with 2+ "::" are ambiguous
  97         }
  98
  99         /**
 100          * Given a string, determine if it as valid IP in IPv4 only.
 101          * Note: Unlike isValid(), this looks for networks too.
 102          * @param $ip string possible IP address
 103          * @return string
 104          */
 105         public static function isIPv4( $ip ) {
 106                 if ( !$ip ) {
 107                         return false;
 108                 }
 109                 return preg_match( '/^' . RE_IP_ADD . '(\/' . RE_IP_PREFIX . '|)$/', $ip );
 110         }
 111
 112         /**
 113          * Given an IP address in dotted-quad notation, returns an IPv6 octet.
 114          * See http://www.answers.com/topic/ipv4-compatible-address
 115          * IPs with the first 92 bits as zeros are reserved from IPv6
 116          * @param $ip quad-dotted IP address.
 117          * @return string
 118          */
 119         public static function IPv4toIPv6( $ip ) {
 120                 if ( !$ip ) {
 121                         return null;
 122                 }
 123                 // Convert only if needed
 124                 if ( self::isIPv6( $ip ) ) {
 125                         return $ip;
 126                 }
 127                 // IPv4 CIDRs
 128                 if ( strpos( $ip, '/' ) !== false ) {
 129                         $parts = explode( '/', $ip, 2 );
 130                         if ( count( $parts ) != 2 ) {
 131                                 return false;
 132                         }
 133                         list( $network, $bits ) = $parts;
 134                         $network = self::toUnsigned( $network );
 135                         if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 136                                 $bits += 96;
 137                                 return self::toOctet( $network ) . "/$bits";
 138                         } else {
 139                                 return false;
 140                         }
 141                 }
 142                 return self::toOctet( self::toUnsigned( $ip ) );
 143         }
 144
 145         /**
 146          * Given an IPv6 address in octet notation, returns an unsigned integer.
 147          * @param $ip octet ipv6 IP address.
 148          * @return string
 149          */
 150         public static function toUnsigned6( $ip ) {
 151                 if ( !$ip ) {
 152                         return null;
 153                 }
 154                 $ip = explode( ':', self::sanitizeIP( $ip ) );
 155                 $r_ip = '';
 156                 foreach ( $ip as $v ) {
 157                         $r_ip .= str_pad( $v, 4, 0, STR_PAD_LEFT );
 158                 }
 159                 $r_ip = wfBaseConvert( $r_ip, 16, 10 );
 160                 return $r_ip;
 161         }
 162
 163         /**
 164          * Given an IPv6 address in octet notation, returns the expanded octet.
 165          * IPv4 IPs will be trimmed, thats it...
 166          * @param $ip string IP address in quad or octet form (CIDR or not).
 167          * @return string
 168          */
 169         public static function sanitizeIP( $ip ) {
 170                 $ip = trim( $ip );
 171                 if ( $ip === '' ) {
 172                         return null;
 173                 }
 174                 if ( self::isIPv4( $ip ) || !self::isIPv6( $ip ) ) {
 175                         return $ip; // nothing else to do for IPv4 addresses or invalid ones
 176                 }
 177                 // Remove any whitespaces, convert to upper case
 178                 $ip = strtoupper( $ip );
 179                 // Expand zero abbreviations
 180                 $abbrevPos = strpos( $ip, '::' );
 181                 if ( $abbrevPos !== false ) {
 182                         // We know this is valid IPv6. Find the last index of the
 183                         // address before any CIDR number (e.g. "a:b:c::/24").
 184                         $CIDRStart = strpos( $ip, "/" );
 185                         $addressEnd = ( $CIDRStart !== false )
 186                                 ? $CIDRStart - 1
 187                                 : strlen( $ip ) - 1;
 188                         // If the '::' is at the beginning...
 189                         if( $abbrevPos == 0 ) {
 190                                 $repeat = '0:';
 191                                 $extra = '';
 192                                 $pad = 9; // 7+2 (due to '::')
 193                         // If the '::' is at the end...
 194                         } elseif( $abbrevPos == ( $addressEnd - 1 ) ) {
 195                                 $repeat = ':0';
 196                                 $extra = '';
 197                                 $pad = 9; // 7+2 (due to '::')
 198                         // If the '::' is in the middle...
 199                         } else {
 200                                 $repeat = ':0';
 201                                 $extra = ':';
 202                                 $pad = 8; // 6+2 (due to '::')
 203                         }
 204                         $ip = str_replace( '::',
 205                                 str_repeat( $repeat, $pad - substr_count( $ip, ':' ) ) . $extra,
 206                                 $ip
 207                         );
 208                 }
 209                 // Remove leading zereos from each bloc as needed
 210                 $ip = preg_replace( '/(^|:)0+' . RE_IPV6_WORD . '/', '$1$2', $ip );
 211                 return $ip;
 212         }
 213
 214         /**
 215          * Given an unsigned integer, returns an IPv6 address in octet notation
 216          * @param $ip_int integer IP address.
 217          * @return string
 218          */
 219         public static function toOctet( $ip_int ) {
 220                 // Convert to padded uppercase hex
 221                 $ip_hex = wfBaseConvert( $ip_int, 10, 16, 32, false );
 222                 // Separate into 8 octets
 223                 $ip_oct = substr( $ip_hex, 0, 4 );
 224                 for ( $n = 1; $n < 8; $n++ ) {
 225                         $ip_oct .= ':' . substr( $ip_hex, 4 * $n, 4 );
 226                 }
 227                 // NO leading zeroes
 228                 $ip_oct = preg_replace( '/(^|:)0+' . RE_IPV6_WORD . '/', '$1$2', $ip_oct );
 229                 return $ip_oct;
 230         }
 231
 232         /**
 233          * Convert an IPv4 or IPv6 hexadecimal representation back to readable format
 234          * @param $hex string number, with "v6-" prefix if it is IPv6
 235          * @return string quad-dotted (IPv4) or octet notation (IPv6)
 236          */
 237         public static function formatHex( $hex ) {
 238                 if ( substr( $hex, 0, 3 ) == 'v6-' ) { // IPv6
 239                         return self::hexToOctet( substr( $hex, 3 ) );
 240                 } else { // IPv4
 241                         return self::hexToQuad( $hex );
 242                 }
 243         }
 244
 245         /**
 246          * Converts a hexadecimal number to an IPv6 address in octet notation
 247          * @param $ip_hex string hex IP
 248          * @return string (of format a:b:c:d:e:f:g:h)
 249          */
 250         public static function hexToOctet( $ip_hex ) {
 251                 // Convert to padded uppercase hex
 252                 $ip_hex = str_pad( strtoupper( $ip_hex ), 32, '0' );
 253                 // Separate into 8 octets
 254                 $ip_oct = substr( $ip_hex, 0, 4 );
 255                 for ( $n = 1; $n < 8; $n++ ) {
 256                         $ip_oct .= ':' . substr( $ip_hex, 4 * $n, 4 );
 257                 }
 258                 // NO leading zeroes
 259                 $ip_oct = preg_replace( '/(^|:)0+' . RE_IPV6_WORD . '/', '$1$2', $ip_oct );
 260                 return $ip_oct;
 261         }
 262
 263         /**
 264          * Converts a hexadecimal number to an IPv4 address in quad-dotted notation
 265          * @param $ip string Hex IP
 266          * @return string (of format a.b.c.d)
 267          */
 268         public static function hexToQuad( $ip ) {
 269                 $s = '';
 270                 for ( $i = 0; $i < 4; $i++ ) {
 271                         if ( $s !== '' ) {
 272                                 $s .= '.';
 273                         }
 274                         $s .= base_convert( substr( $ip, $i * 2, 2 ), 16, 10 );
 275                 }
 276                 return $s;
 277         }
 278
 279         /**
 280          * Convert a network specification in IPv6 CIDR notation to an
 281          * integer network and a number of bits
 282          * @return array(string, int)
 283          */
 284         public static function parseCIDR6( $range ) {
 285                 # Explode into <expanded IP,range>
 286                 $parts = explode( '/', IP::sanitizeIP( $range ), 2 );
 287                 if ( count( $parts ) != 2 ) {
 288                         return array( false, false );
 289                 }
 290                 list( $network, $bits ) = $parts;
 291                 $network = self::toUnsigned6( $network );
 292                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 128 ) {
 293                         if ( $bits == 0 ) {
 294                                 $network = "0";
 295                         } else {
 296                                 # Native 32 bit functions WONT work here!!!
 297                                 # Convert to a padded binary number
 298                                 $network = wfBaseConvert( $network, 10, 2, 128 );
 299                                 # Truncate the last (128-$bits) bits and replace them with zeros
 300                                 $network = str_pad( substr( $network, 0, $bits ), 128, 0, STR_PAD_RIGHT );
 301                                 # Convert back to an integer
 302                                 $network = wfBaseConvert( $network, 2, 10 );
 303                         }
 304                 } else {
 305                         $network = false;
 306                         $bits = false;
 307                 }
 308                 return array( $network, (int)$bits );
 309         }
 310
 311         /**
 312          * Given a string range in a number of formats, return the start and end of
 313          * the range in hexadecimal. For IPv6.
 314          *
 315          * Formats are:
 316          *     2001:0db8:85a3::7344/96                                   CIDR
 317          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 318          *     2001:0db8:85a3::7344/96                                   Single IP
 319          * @return array(string, int)
 320          */
 321         public static function parseRange6( $range ) {
 322                 # Expand any IPv6 IP
 323                 $range = IP::sanitizeIP( $range );
 324                 // CIDR notation...
 325                 if ( strpos( $range, '/' ) !== false ) {
 326                         list( $network, $bits ) = self::parseCIDR6( $range );
 327                         if ( $network === false ) {
 328                                 $start = $end = false;
 329                         } else {
 330                                 $start = wfBaseConvert( $network, 10, 16, 32, false );
 331                                 # Turn network to binary (again)
 332                                 $end = wfBaseConvert( $network, 10, 2, 128 );
 333                                 # Truncate the last (128-$bits) bits and replace them with ones
 334                                 $end = str_pad( substr( $end, 0, $bits ), 128, 1, STR_PAD_RIGHT );
 335                                 # Convert to hex
 336                                 $end = wfBaseConvert( $end, 2, 16, 32, false );
 337                                 # see toHex() comment
 338                                 $start = "v6-$start";
 339                                 $end = "v6-$end";
 340                         }
 341                 // Explicit range notation...
 342                 } elseif ( strpos( $range, '-' ) !== false ) {
 343                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 344                         $start = self::toUnsigned6( $start );
 345                         $end = self::toUnsigned6( $end );
 346                         if ( $start > $end ) {
 347                                 $start = $end = false;
 348                         } else {
 349                                 $start = wfBaseConvert( $start, 10, 16, 32, false );
 350                                 $end = wfBaseConvert( $end, 10, 16, 32, false );
 351                         }
 352                         # see toHex() comment
 353                         $start = "v6-$start";
 354                         $end = "v6-$end";
 355                 } else {
 356                         # Single IP
 357                         $start = $end = self::toHex( $range );
 358                 }
 359                 if ( $start === false || $end === false ) {
 360                         return array( false, false );
 361                 } else {
 362                         return array( $start, $end );
 363                 }
 364         }
 365
 366         /**
 367          * Validate an IP address.
 368          * @return boolean True if it is valid.
 369          */
 370         public static function isValid( $ip ) {
 371                 return ( preg_match( '/^' . RE_IP_ADD . '$/', $ip ) || preg_match( '/^' . RE_IPV6_ADD . '$/', $ip ) );
 372         }
 373
 374         /**
 375          * Validate an IP Block.
 376          * @return boolean True if it is valid.
 377          */
 378         public static function isValidBlock( $ipblock ) {
 379                 return ( count( self::toArray( $ipblock ) ) == 1 + 5 );
 380         }
 381
 382         /**
 383          * Determine if an IP address really is an IP address, and if it is public,
 384          * i.e. not RFC 1918 or similar
 385          * Comes from ProxyTools.php
 386          */
 387         public static function isPublic( $ip ) {
 388                 $n = self::toUnsigned( $ip );
 389                 if ( !$n ) {
 390                         return false;
 391                 }
 392
 393                 // ip2long accepts incomplete addresses, as well as some addresses
 394                 // followed by garbage characters. Check that it's really valid.
 395                 if( $ip != long2ip( $n ) ) {
 396                         return false;
 397                 }
 398
 399                 static $privateRanges = false;
 400                 if ( !$privateRanges ) {
 401                         $privateRanges = array(
 402                                 array( '10.0.0.0',    '10.255.255.255' ),   # RFC 1918 (private)
 403                                 array( '172.16.0.0',  '172.31.255.255' ),   #     "
 404                                 array( '192.168.0.0', '192.168.255.255' ),  #     "
 405                                 array( '0.0.0.0',     '0.255.255.255' ),    # this network
 406                                 array( '127.0.0.0',   '127.255.255.255' ),  # loopback
 407                         );
 408                 }
 409
 410                 foreach ( $privateRanges as $r ) {
 411                         $start = self::toUnsigned( $r[0] );
 412                         $end = self::toUnsigned( $r[1] );
 413                         if ( $n >= $start && $n <= $end ) {
 414                                 return false;
 415                         }
 416                 }
 417                 return true;
 418         }
 419
 420         /**
 421          * Split out an IP block as an array of 4 bytes and a mask,
 422          * return false if it can't be determined
 423          *
 424          * @param $ipblock string A quad dotted/octet IP address
 425          * @return array
 426          */
 427         public static function toArray( $ipblock ) {
 428                 $matches = array();
 429                 if( preg_match( '/^' . RE_IP_ADD . '(?:\/(?:' . RE_IP_PREFIX . '))?' . '$/', $ipblock, $matches ) ) {
 430                         return $matches;
 431                 } elseif ( preg_match( '/^' . RE_IPV6_ADD . '(?:\/(?:' . RE_IPV6_PREFIX . '))?' . '$/', $ipblock, $matches ) ) {
 432                         return $matches;
 433                 } else {
 434                         return false;
 435                 }
 436         }
 437
 438         /**
 439          * Return a zero-padded hexadecimal representation of an IP address.
 440          *
 441          * Hexadecimal addresses are used because they can easily be extended to
 442          * IPv6 support. To separate the ranges, the return value from this
 443          * function for an IPv6 address will be prefixed with "v6-", a non-
 444          * hexadecimal string which sorts after the IPv4 addresses.
 445          *
 446          * @param $ip Quad dotted/octet IP address.
 447          * @return hexidecimal
 448          */
 449         public static function toHex( $ip ) {
 450                 $n = self::toUnsigned( $ip );
 451                 if ( $n !== false ) {
 452                         $n = self::isIPv6( $ip ) ? 'v6-' . wfBaseConvert( $n, 10, 16, 32, false ) : wfBaseConvert( $n, 10, 16, 8, false );
 453                 }
 454                 return $n;
 455         }
 456
 457         /**
 458          * Given an IP address in dotted-quad/octet notation, returns an unsigned integer.
 459          * Like ip2long() except that it actually works and has a consistent error return value.
 460          * Comes from ProxyTools.php
 461          * @param $ip Quad dotted IP address.
 462          * @return integer
 463          */
 464         public static function toUnsigned( $ip ) {
 465                 // Use IPv6 functions if needed
 466                 if ( self::isIPv6( $ip ) ) {
 467                         return self::toUnsigned6( $ip );
 468                 }
 469                 if ( $ip == '255.255.255.255' ) {
 470                         $n = -1;
 471                 } else {
 472                         $n = ip2long( $ip );
 473                         if ( $n == -1 || $n === false ) { # Return value on error depends on PHP version
 474                                 $n = false;
 475                         }
 476                 }
 477                 if ( $n < 0 ) {
 478                         $n += pow( 2, 32 );
 479                 }
 480                 return $n;
 481         }
 482
 483         /**
 484          * Convert a dotted-quad IP to a signed integer
 485          * Returns false on failure
 486          */
 487         public static function toSigned( $ip ) {
 488                 if ( $ip == '255.255.255.255' ) {
 489                         $n = -1;
 490                 } else {
 491                         $n = ip2long( $ip );
 492                         if ( $n == -1 ) {
 493                                 $n = false;
 494                         }
 495                 }
 496                 return $n;
 497         }
 498
 499         /**
 500          * Convert a network specification in CIDR notation to an integer network and a number of bits
 501          * @return array(int, int)
 502          */
 503         public static function parseCIDR( $range ) {
 504                 $parts = explode( '/', $range, 2 );
 505                 if ( count( $parts ) != 2 ) {
 506                         return array( false, false );
 507                 }
 508                 list( $network, $bits ) = $parts;
 509                 $network = self::toSigned( $network );
 510                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 511                         if ( $bits == 0 ) {
 512                                 $network = 0;
 513                         } else {
 514                                 $network &= ~( ( 1 << ( 32 - $bits ) ) - 1);
 515                         }
 516                         # Convert to unsigned
 517                         if ( $network < 0 ) {
 518                                 $network += pow( 2, 32 );
 519                         }
 520                 } else {
 521                         $network = false;
 522                         $bits = false;
 523                 }
 524                 return array( $network, $bits );
 525         }
 526
 527         /**
 528          * Given a string range in a number of formats, return the start and end of
 529          * the range in hexadecimal.
 530          *
 531          * Formats are:
 532          *     1.2.3.4/24          CIDR
 533          *     1.2.3.4 - 1.2.3.5   Explicit range
 534          *     1.2.3.4             Single IP
 535          *
 536          *     2001:0db8:85a3::7344/96                                   CIDR
 537          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 538          *     2001:0db8:85a3::7344                                      Single IP
 539          * @return array(string, int)
 540          */
 541         public static function parseRange( $range ) {
 542                 // Use IPv6 functions if needed
 543                 if ( self::isIPv6( $range ) ) {
 544                         return self::parseRange6( $range );
 545                 }
 546                 if ( strpos( $range, '/' ) !== false ) {
 547                         # CIDR
 548                         list( $network, $bits ) = self::parseCIDR( $range );
 549                         if ( $network === false ) {
 550                                 $start = $end = false;
 551                         } else {
 552                                 $start = sprintf( '%08X', $network );
 553                                 $end = sprintf( '%08X', $network + pow( 2, ( 32 - $bits ) ) - 1 );
 554                         }
 555                 } elseif ( strpos( $range, '-' ) !== false ) {
 556                         # Explicit range
 557                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 558                         if( self::isIPAddress( $start ) && self::isIPAddress( $end ) ) {
 559                                 $start = self::toUnsigned( $start );
 560                                 $end = self::toUnsigned( $end );
 561                                 if ( $start > $end ) {
 562                                         $start = $end = false;
 563                                 } else {
 564                                         $start = sprintf( '%08X', $start );
 565                                         $end = sprintf( '%08X', $end );
 566                                 }
 567                         } else {
 568                                 $start = $end = false;
 569                         }
 570                 } else {
 571                         # Single IP
 572                         $start = $end = self::toHex( $range );
 573                 }
 574                 if ( $start === false || $end === false ) {
 575                         return array( false, false );
 576                 } else {
 577                         return array( $start, $end );
 578                 }
 579         }
 580
 581         /**
 582          * Determine if a given IPv4/IPv6 address is in a given CIDR network
 583          * @param $addr The address to check against the given range.
 584          * @param $range The range to check the given address against.
 585          * @return bool Whether or not the given address is in the given range.
 586          */
 587         public static function isInRange( $addr, $range ) {
 588                 // Convert to IPv6 if needed
 589                 $hexIP = self::toHex( $addr );
 590                 list( $start, $end ) = self::parseRange( $range );
 591                 return ( strcmp( $hexIP, $start ) >= 0 &&
 592                         strcmp( $hexIP, $end ) <= 0 );
 593         }
 594
 595         /**
 596          * Convert some unusual representations of IPv4 addresses to their
 597          * canonical dotted quad representation.
 598          *
 599          * This currently only checks a few IPV4-to-IPv6 related cases.  More
 600          * unusual representations may be added later.
 601          *
 602          * @param $addr something that might be an IP address
 603          * @return valid dotted quad IPv4 address or null
 604          */
 605         public static function canonicalize( $addr ) {
 606                 if ( self::isValid( $addr ) ) {
 607                         return $addr;
 608                 }
 609
 610                 // Turn mapped addresses from ::ce:ffff:1.2.3.4 to 1.2.3.4
 611                 if ( strpos( $addr, ':' ) !== false && strpos( $addr, '.' ) !== false ) {
 612                         $addr = substr( $addr, strrpos( $addr, ':' ) + 1 );
 613                         if( self::isIPv4( $addr ) ) {
 614                                 return $addr;
 615                         }
 616                 }
 617
 618                 // IPv6 loopback address
 619                 $m = array();
 620                 if ( preg_match( '/^0*' . RE_IPV6_GAP . '1$/', $addr, $m ) ) {
 621                         return '127.0.0.1';
 622                 }
 623
 624                 // IPv4-mapped and IPv4-compatible IPv6 addresses
 625                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . '(' . RE_IP_ADD . ')$/i', $addr, $m ) ) {
 626                         return $m[1];
 627                 }
 628                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . RE_IPV6_WORD . ':' . RE_IPV6_WORD . '$/i', $addr, $m ) ) {
 629                         return long2ip( ( hexdec( $m[1] ) << 16 ) + hexdec( $m[2] ) );
 630                 }
 631
 632                 return null;  // give up
 633         }
 634 }